Azo dye and method for its preparation



Patented Oct. 22, 1935 AZO DYE AND METHOD FOR ITS PREPARATION Francis Hervey Smith, Woodstown, N. J., and

Crayton Knox Black, Wilmington, Del.-, assignors to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application July 26, 1932, Serial No. 624,900

12 Claims. (01. 26072) This invention relates to azo dyes, and more particularly refers to azo dyes especially suitable for dyeing leather.

In the past when leather was dyed it was frequently necessary to use a mixture of dyes, as a result of which the resulting color was uneven and often had very poor stability. This was particularly true where it was desired to dye leather various shades of brown.

It is an object of this invention to produce dyes which are especially adapted for dyeing leather in even shades, particularly the various shades of brown. It is a further object to produce dyes which may be used to dye wool and other mate- .5 rial. Additional objects will appear hereinafter.

These objects are accomplished by the present invention wherein a dye of the following general formula is produced:

reference to the following examples, in which the 40 quantities are stated in parts by weight:

Example I 17.3 parts of sulfanilic acid were stirred in 250,

45 parts of water. 4 parts of sodium hydroxide were added which dissolved the sulfanilic acid. The solution was iced to approximately 5 C. and made acid with 9 parts 100% hydrochloric acid. It was then diazotized by the addition of 6.9 parts 50 of sodium nitride. To this diazo added a so lution of 11 parts of resorcin in 100 parts of water. After the addition of the resorcin, approximately 25 partsof sodium acetate were added. Coupling was completed within 30 minutes. 12 parts of sodium hydroxide were added, 5 which dissolved the dye.

19.9 parts of picramic acid were stirred in 400 parts of water and 4 parts of sodium hydroxide added. The solution was then acidified with 9 parts of 100% hydrochloric acid and diazotized at 10 15-20 C. with 6.9 parts of sodium nitrite. This diazo was added to the above alkaline solution. After stirring one hour, hydrochloric acid was added until the combination was slightly acid and then freshly slalied lime was added, until 15 alkaline to brilliant yellow papers. The dye was heated to 95 C. and .a solution of 15.9 parts of Ca(SH)z added. Reduction was completed in 2 hours after which the dye was salted by volumeandfiltered. The press cake was reslurried 20 in 400 parts of water, made acid with approximately 9 parts of 100% hydrochloric acid and diazotized at 20 C. with 6.9 parts of sodium nitrite for one hour. A solution of 20 parts of meta phenylene diamine sulfonic acid in 200 parts of water was added, and then sodium acetate until the mixture was no longer acid to Congo red paper. The dye was stirred one hour and then filtered cold without the addition of salt. v

The dry dye was a black powder which dissolvedin water to give a dark brown solution and in concentrated sulfuric acid to give a reddishbrown solution.

It dyed leather a dark chocolate-brown. Its probable formula is as follows:

0n reducing with sodium hydrosulfite the follow ing compounds are obtained:

Sulfanilic acid, 2,4-diarnino-resorcin, 2,4,6-triamino-phenol, 2,4,5-triamino benzene sulfonic acid.

. I Example 2 V 12 parts of meta -phenylene-diamine were substituted for the 20 parts of meta phenylene diamine sulfonic acid in Example 1.

The dry dye was a black powder which dissolved in water to give a yellowish-brown solution and in concentrated sulfuric acid to give a reddish-brown solution.

It dyed leather a yellow-brown.

Its probable formula. is as follows:

on mi. I=N N=N V V on m SO;HO-N=N 7 V H t V on reducing with sodium hydrosulflte the following pounds are obtained: l I

Sulfanilic acid, 2,4-diamino-resorcin, 2,4,6-triamino-phenol, 2,3,5-triamino-benzene. 7

Example 3 22.3 parts of a technical mixture of l-aminonaphthalene-6(and '7) -sulfonic acid were substituted for the 17.3 parts of sulfanilic'acid in Example 1. r

The dry dye was a black powder which dissolved in water to give a dark brown solution and in concentrated sulfuric acid to give a violet solution.

It dyed leather a yellow-brown.

Its probable formula is as follows:

7 0H NH! 7 V V N=N N ==N mm 7 N0: son

On reducing with sodium hydrosulflte the following compounds are obtained:

Mixed Cleves acid, 2,4-diamino-resorcin, 2,4,6- triamino-phenol, 2,4,5-triamino-benzene-sulfonic acid.

Example 4 15.4 parts of p-nitro-o-amino-phenol were substituted for the 19.9 parts of picramic acid in Example 1.

r The dry dye was a dark brown powder which dissolved in water to give a yellow-brown solution and in concentrated sulfuric acid-to give a dark brown solution.

I l on j I 7 NEN V 7 0H BOuHQ-N-N x Q n r It dyed leather a reddish-brown. Its probable formula is as follows:

On reducing with sodium hydrosulfite the following products are obtained:

Sulfanilic acid, 2,4-diamino-resorcin, 2,4-diamino-phenol, 2,4,5-triaminobenzene sulfonic On reducing with sodium hydrosulflte the following compounds are obtained: Naphthionic acid, 2,4-diamino-resorcin, 2,4,6-

triamino-phenol, 2,4,5-triamino-benzene-sulfonic acid. 35

Example 6 22 parts of meta-toluylene-diamine-sulfonic acid were substituted for the 20 partsv of metaphenylene-diamine-sulfonic acid in Example 5.

The dry dye was'a black powder which dissolved in water to give a red-brown solution and in concentrated sulfuric acid to give a red-brown solution.

It dyed leather a dark chocolate brown.

Its probable formula is as follows:

On reducing with sodium hydrosulfite the following compounds are obtained:

. Naphthionic, acid, 2,4-diamino-resorcin, 2,4,6-' triamino phenol, 2,3,4-triamino-toluene5-sulfonic acid. A

Example 7 22.1, parts of 2-chlor-5-toluidine-4-sulfonic acid were substituted for the 17.3 parts of sulfanilic acid in Example 1. 1 The 'dry dye was a black powder which dissolved in water to give a'yellow-brown solution and in concentrated sulfuric acid to give a redbrown solution. 7

It dyed leather 8. yellow'brown.

g 1 on N=N N=N 5 son: on

N=N V Nth" I c1 H I OH: I I

Its probable formula is asfol1ows:

On reducing with sodium hydrosulflte the following compounds are obtained; 3 I

2-chlor-5-toluidine-4-sulfonic acid, 2,4 d1 amino-resorcin, 2,4,6-triamino-phenol, 2,4,5-trlamino-benzene-sulfomc acid.

Example 8 18.7 parts of p-toluidine-m-sulfonic acid were substituted for the 17.3 parts of sulfanilic acid in Example 1.

The dry dye was a black powder which dissolved in water to give-a yellow-brown solution .and in concentrated sulfuric acid to give a redbrown solution. v

It dyed leather a yellow-brown.

Its probable formula. is as follows:

On reducing with sodium hydrosulfite the following compounds are obtained:

P-toluidine-m-sulfonic acid, 2,4-diamino-resorcin, 2,4,6 triamino phenol, 2,4,5 triamino benzene-sulfonic acid.

Example 9 V 30.3 parts of amino G salt were substituted for the 17.3 parts of sulfanilic acid in Example 1.

The dry dye was a black, powder which dissolved in water to give a dark brown solution and in concentrated sulfuric acid to give a red-brown solution.

It dyed leather a dark chocolate brown.

Its probable formula is as follows:

SOIH

On reducing with sodium hydrosulfite thefollow- Ming compounds are obtained: 1 a.

'Amino G: salt, :2,4.-diamino-resorcin; 2,4,6-triamino phenol, '2,4,5-triamino-benzene-sulfonic acid.

Example 10 i 15.4 parts of resorcylic acid were substituted for the 11 parts resorcin in Example 1.

I The dry dye'was a black powder which dis-- solved in water to give a yellow-brown solution and'in concentrated sulfuric acid to give a redbrown-solution.' 3 I It dyed leather a deep chestnut-brown. Its probable formula is as follows;

Onreducing with sodium hydrosulfite the following compounds are obtained:

Sulfanilic acid, dihydroxy-diamino-benzoic acid, 2,4,6-triamino-phenol, 2,4,5-triamino-benw zene sulfonic acid.

Example 11 10.? parts o-toluidine were substituted for the 17.3 parts of sulfanilic acid in Example 10.

The dry dye was a dark brown powder which dissolved in water to give a yellow-brown solution and in concentrated sulfuric acid'to give a dark brown solution.

It dyed leather a yellow-brown.

Its probable formula is as follows:

' OH NH:

CIHl OH on \NH| On reducing'with sodium hydrosul-flte the following compoundsv are obtained: w

I. Sulfanilic acid,. 2,4-diamin'o-resorcin, 52,4;6-

triamino phenol, amino sulfophenylmeth'yl-...

pyrazolone.

Ex m

35 parts of R salt dissolved in excess soda ash solution were substitutedfor the 20 parts of meta phenylene diamine sulfonic acidin Example 1. No Sodium acetatewas used in the last coupling.

The dry dye was a black powder whicli dissolved water to give a. yellow-brownsolution and in concentratedsulfuric acid to'give a redbrown solution. Y W It dyed leather an olive-brown. v

Its probable formula is as follows:

azotization was continued for, liminutes .at -20 C., thena solution of 11 parts of resorcin in 100 parts of water was added. Sodium acetate was added until the solution was no longer acid to Congo red paper. Coupling was completed in 30 .minutes. The combination was then" made alkaline with sodium hydroxide and heated to 90 C. where it was held for 30 minutes 'to'complete saponification. acidified with hydrochloric acid and diazotized with 6.9 parts of sodium nitrite at C. for one hour. vi

.The first combination .was made alkaline to brilliant yellow with sodium hydroxide, cooled to 20 C. and the above diazo added. Coupling- On reducing with sodium hydrosulfite the following products areobtained:

Sulfanilic acid, 2,4-diamino-resorcin, 2,4,6-

triamino-phenol, amino R salt.

Example 14' 15 parts of resorcin were substituted for the 20 parts of meta phenylene diamine sulfonio acid in Example 1.

- The dry dye was a black powder which dissolved in water to give a brown solution and in concentrated sulfuric acid to give a dark brown solution.

It dyed leather a very dark'brown. Its probable formula is as follows:

On reducing with sodium hydrosulfite the following compounds are obtained:

V Sulfanilic acid, 2,4-diamino-resorcin, 2,4,6- tri'amino-phenol, amino-resorcin.

Example 15 17.3 parts of'sulfanilic acid were diazotized and coupled to 11 parts of resorcin as in Example 1. a x 28 parts of 1-acetylamino-4-amino-naphthalene- 'l-sulfonic acid were stirred in 400 parts of water. '19 parts ofv 100%. hydrochloric acid were added and then ;6..9;parts ofsodium nitrite .Di-r.

on on N='N N=N was very rapid. The dye was isolated bythe It was cooled to 20 C.

addition of salt and thenhydrochloric acid until I neutral to litmus.

The dry dye was a black powder which dissolved in water; to give a yellow-brown and in concentrated sulfuric acid to give a dark brown solution. r v i It dyed leather a good medium brown. Its probable formulais as follows:

H N NH On reducing with sodium hydrosulfite the following compounds are obtained:

Sulfanilic acid, 2,4-diamino-res'orcin, aminoresorcin, 1,4 diamino naphthalene 7 sulfonic acid.

Ecam ze 16 13.8 parts of p-nitro-aniline were substituted for the 19.9 parts of picramic acid in Example 1. The dry dye was a black powder which dis solved in water to give a red-brown solution and in concentrated sulfuric acid to givea blue solution. i 7

It dyed leather a reddish brown. 1 Its probable formula-is as follows:

K On reducing with sodium 'hydrosulfite the following compounds are obtained: v j H Sulfanilic acid, 2,4 diamino-resorcin,"P-phelen'e diamine, .4.5:t ia i -b n ene:su1 0m acid. a

benzene-sulfonic 2,4,5-triamino-benzene-sulfonic acid.

Example 17 SOaH On reducing with sodium hydrosulflte the following compounds are obtained:

Sulfanilic acid, 3,5-diaminoe2:4-dihydroxy acid, 2,4,6-trlamino-phenol,

Example 18 14.5 parts of l,3-dihydroxy-4-chlorobenzene were substituted for the 11 parts of resorcin in Example 1.

The dry dye was a black powder which dissolved in water to give a yellow-brown solution and in concentrated sulfuric acid to give a redbrown solution.

It dyed leather a dark brown.

Its probable formula is as follows:

OH or: NH: 40 I som- N=N N=N N=N H i v NH: 45

On reducing with sodium hydrosulfite the following compounds are obtained:

Sulfanilic acid, 3,5-diamino-2,4-dihydroxy-1- chlor-benzene, 2,4,6-triamino-phenol, 2,4,5-triamino-benzene sulfonic acid.

Example 19 12.5 parts of orcinol were substituted for the 11 parts of resorcin in Example 1;

The dry dye was a black powder which dissolved in water to give a yellow-brown solution and inconcentrated sulfuric acid to give a yellow-brown solution.

It dyed leather a yellow-brown.

Its probable formula is as follows:

OH on NH| SO;HON= N=N N=N l NH:

SOzH

On reducing with sodium hydrosulfite the following products are obtained:' j

Sulfanilic acid 2,4 dihydroxy-3,5-diamino-toluene, 2;4,6 '-trlamino-pheno1, 2,4=,5-triamino-benzene-sulfonic acid.

Example 20 11.0 parts of 1,2dihydroxy-benzene were sub- 5 stituted for the -11 parts of resorcin in Example #1.

The dry dye is a black powder which dissolves in water to give a yellow-brown solution and.

in concentrated sulfuric acid to give a red-brown Y solution.

It dyes leather a yellow-brown. Its probable formula is as follows:

HO OH NH:

N=N N=N- H0!S-C N=N NH,

NO: OIH

On reduction with sodium hydrosulphite the following compounds are obtained:

Sulfanilic acid, 1,2-dihydroxy-4,5-diaminobenzene, 2,4,6-triamino-phenol, 2,4,5-triamino-benzene-sulfonic acid.

In place of the reactants used in the above examples numerous other compounds may be substituted therefor with satisfactory results. For instance, in place of the compounds used for R, R and R" other members of the benzene, naphthalene, anthracene, phenyl-naphthyl,

referred to. As is well known to one skilled in the art, this component designated by R' may be diazotized and coupled with the component desrebates by it" "or. it: my coupled with the" azo compound previously formed by coupling the component designated by R with the dihydroxy M benzene. 'Iihe resulting compound is treated; to '5 convert thenitro or mono-acyl aminogroup to theamino group, after which it is diazotized and coupled to form the trisazo dye. The methods of; treating the nitro grouper the mono-acylamino group to convert it to an amino group are may be used. Among the compounds which may be substituted fo'r R" with good results are the following: V

fl-naphthol, a-naphthol, Z-naphthol-G-sulfonic acid, 2-naphthol-8-sulfonic-acid, 2-naphthol-5- sulfonic acid, 2-naphthol-7-sulfonic acid, 2- naphthol-Bfi-disulfonic acid, 2-naphthol-4,8-disulfonic acid,-2 naphthol-6,8-disulfonic acid, 2-

H naphthol-3,6,8-trisulfonic acid, 1-naphthol-2- sosulfonic acid, l-naphtholl-sulfonic acid, 1- naphthol-5-sulfonic acid, l-naphthol-3,6,8-trisulfonic acid, -naphthylamine, p-naphthyl- .amine, l amino-5enaphthol-7-sulfonic acid, 1-

amino-7-naphthol-3-sulfonic acid, naphthol--sulfonic acid, l-amino-8-naphtholfi-sulfonic acid, 2-amino -3-naphthol-6-sulfonic acid, 2-amino-5-naphthol-7-sulionic acid, 2-

" amino-7-naphthol-3-sulfonic acid, p-hydroxynaphthoic acid, J -acid urea, P-amino-benzoyl-J- acid, phenyl-J-acid, salicylic acid, 1,6-Cleves acid, 1,7-Cleves acid, naphthionic acid, phenylmethyl-pyrazolone, chlor-sulfophenyl-methylpyrazolone, acetoacetanilide, acetoacet-orthochlor-anilide, methyl indole.

' stituted on the benzene nucleus other groups, previously designated by X, may be substituted thereon. Among these substituents are the following:' halogen, alkyl, alkoxy, nitro, carboxyl,

sulfonic, and hydroxyl. For this component the following compounds give excellent results:

Dihydroxy nitro benzene, dihydroxy anisidines or phenetidines, dihydroxy bromgbenzenes, dihydroxy fluor benzenes. V

e Other dihydroxy substituted benzenes to which two equivalents of diazonium salts can be coupled may be used for this component without impairing the utility of the resulting product.

The products of the present invention are cspecially desirable for dyeing leather, since they eliminate the necessity of' using a mixture of dyes where certain colors, particularly the various shades of brown, are required. They dye 7 leather in even shades of excellent stability. In

6.5 addition to the dyeing of leather they may also be used for various other purposes, such as, the dyeing of wool.

As many apparent and widely diflerent em- 7 bodiments of this invention may be made without departing from the spirit thereof, it is to be understood that we do not limit ourselves to the foregoingexamples or description except as indicatedinthe iollowing claims.

Weclaim: i r f 76 1. A prom for producing azo dyes which 1-amino-8- comprises coupling a diazotized aromatic amine witha dihydroxy benzene, coupling this compound with a member selected from the group consisting of diazotized aromatic nitro-amines and diazotized mono-acyl-diamines of the ben- '5 zene series, treating the resulting compound to convert the nitro or mono-acyl-amino group to an amino group, then diazotizing and coupling: with an aromatic coupling componentJ ii 2. A process for producing azo dyes which 6' comprises coupling a diazotized aromatic amine of the benzene series with a dyhydroxy benzene, coupling this compound with a member selected from the group consisting of diazotized aromatic nitroamines and diazotized mono-acyl-diamines 15' of the benezene series, treatinghthe resulting compound to convert the nitroor mono acylamino groupto an amino group, then diazotizing and coupling with an aromatic coupling component of the benzene series.

3. A process for producing azo dyes which comprises coupling a, member selected from the, group consisting of diazotized amines of the benzene and naphthalene series, with resorcin, coupling this compound with a member selected 25 from the group consisting of diazotized aromatic nitro-amines anddiazotized mono-acyl-diamines of the benzene series, treating the resulting compound to convert the nitro or mom- I acyl-amino group to an amino group, then diazo- 30 tizing and coupling with an aromatic coupling component of the benzene series. V

4. A process for. producing azo dyes'which comprises coupling diazotizedsulfanilic acid with r resorcin, coupling this compound with diamtized p-nitro-o-aminoephenol treating to convert the nitro group to' anamino group, thendiazotizing and coupling with meta-phenylene-diamine-sulfonic acid.

7 5. A process for. producing azo dyes which 40; comprises coupling a diazotized technical mix-' ture. of l-amino-naphthalene-6-sulfbnic acid and 1-amino-naphthalene-7-sulionic acid with resorcin, coupling this compound withdiazo- 45 In addition to the two hydroxy groups sub tized picramic acid, treating to convert the nitro 4.5 group, ortho tothe hydroxy group, to an amino group, then diazotizing and coupling with meta phenylene-diamine-sulfonic acid.

6. A process for producing azo dyes which comprises coupling diazotized sulfanilic acid with 50 resorcin, coupling this compound with diazotized picramic acid, treating to convert the nitro group, ortho to the hydroxy group, to an amino group, then diazotizing' and coupling with resorcin, V I 7 h 551 A11 azo y having the following general formula:

H N=N RH r in which R and R' represent aromatic nuclei, R. represents the nucleus 01' a dihydroxy benzene, and R" represents the nucleus of an arcmatic amine of the benzene series.

8. An azo "dye having the following general formula:

in which R, R and R" represent aromatic 9. An azo dye having the following general formula:

10. An azo dye having the following formula: 4

which is a dark brown powder, dissolving in water to give a yellow-brown solution, and in concentrated sulfuric acid to give a dark brown solution.

11. An azo dye having the following formula:

12. An azo dye having the following formula:

which is a black powder, dissolving in water to. 25

give a brown solution and in concentrated sulfuric acid to give a dark brown solution.

FRANCIS HERVEY SMITH.

CRAYTON KNOX BLACK. 0

CERTEMQATE 9F CURRECTWN.

Pateni' N0. 2, 018 234. Qcteber 22, 1935.

FRANCiS EEERVEY SWTE'L ET AL.

It is. hereby certified that error appears in the printed spexzification 0f me mauve numbered patent requiring wrrectian as iolkmvs: Fage i, first wiumn, line 50, for "niirida" mad nitrire; and that the said Letters Patsm': shoukd be read with this correction therein that the same may mnfisrm to the mean! of the case in the Patent Office.

Signed mad ssaled this 17th day of December, A, D. 3935.

Les! ie Frauen (Seal) Easting Commissionar of Patents. 

